Electric vehicle and control method therefor

ABSTRACT

A method of transitioning an electric snowmobile from a drive state to a reverse state comprising receiving at a controller a reverse request from a user interface of the electric snowmobile. Upon receipt of the reverse request, the controller transitions the electric snowmobile from a drive state to a reverse state when a speed signal associated with the electric snowmobile is below a predetermined speed threshold and transitions the electric snowmobile from a drive state to a reverse requested state when a speed signal associated with the electric snowmobile is above a predetermined speed threshold. In the reverse state, the controller drives the electric snowmobile in a reverse direction based on a throttle signal and in the reverse requested state, the controller does not drive operation of the electric snowmobile based on the throttle signal.

FIELD

This specification relates to electric vehicles and, more specifically, to a method of controlling operation of an electric snowmobile.

BACKGROUND

Heat engine based snowmobiles have been around for many decades and have become a very popular sport with amateurs and professionals, as well as a valued utility vehicle. Increased environmental awareness, as well as other factors, motivate the use of electric engines instead of heat engines. Electric engines have several differences from heat engines, both in terms of energy supply, power delivery, and general behavior. For instance, electric engines typically generate significantly less noise than heat engines and have full torque at zero RPM. While earlier technologies have been satisfactory to a certain degree, there always remains room for improvement, including in terms of providing a better user experience in relation with the reverse function in an electric snowmobile.

SUMMARY

In one aspect, the disclosure describes a method of transitioning an electric snowmobile from a drive state to a reverse state, the method comprising: receiving at a controller a reverse request from a user interface of the electric snowmobile; wherein, upon receipt of the reverse request, the controller being operative to: transition the electric snowmobile from a drive state to a reverse state when a speed signal associated with the electric snowmobile is below a predetermined speed threshold, wherein in the reverse state, the controller drives the electric snowmobile in a reverse direction based on a throttle signal; and, transition the electric snowmobile from a drive state to a reverse requested state when a speed signal associated with the electric snowmobile is above a predetermined speed threshold, wherein in the reverse requested state, the controller does not drive operation of the electric snowmobile based on the throttle signal.

In some embodiments, when the electric snowmobile is in the reverse requested state, the controller is further operative to: transition the electric snowmobile from the reverse requested state to the reverse state when the speed signal transitions from above the speed threshold to below the speed threshold.

In some embodiments, when the electric snowmobile is in the drive state, the controller drives the electric snowmobile in a forward direction based on the throttle signal.

In some embodiments, the transition from the drive state to the reverse state is contingent upon determining that a throttle signal is below a throttle threshold.

In some embodiments, the transition from the drive state to the reverse requested state includes changing an indicator configuration in a user interface of the electric snowmobile.

In some embodiments, the changing the indicator configuration includes at least one of changing a configuration of a visual indicator and changing a configuration of an audible indicator.

In some embodiments, when the electric snowmobile is in the reverse requested state, the controller is further operative to: transition the electric snowmobile from the reverse requested state to the reverse state when the speed signal transitions from above the speed threshold to below the speed threshold, and the transition from the reverse requested state to the reverse state includes changing an indicator configuration in the user interface.

In some embodiments, the reverse request can be generated upon operator interaction with a user input on a user interface of the electric snowmobile.

In some embodiments, the speed signal comprises at least one of a vehicle speed and a motor speed.

In some embodiments, driving the electric snowmobile in the reverse direction includes mapping a throttle signal to a corresponding power request based on a power map, and applying the power request to an electric motor of the electric snowmobile.

In some embodiments, when the electric snowmobile is in the reverse requested state, the controller is further operative to: transition the electric snowmobile from the reverse requested state to the drive state when a throttle signal above a throttle threshold value is received.

In some embodiments, when in the reverse requested state, the controller drives the electric motor in a regenerative mode to actively decelerate the electric snowmobile.

Embodiments may include combinations of the above features.

In another aspect, the disclosure describes a snowmobile having a powertrain including an electric motor mechanically engaged with a track, a motoring battery configured for supplying the electric motor with electrical power, a throttle actuator operable to provide a throttle signal changing as a function of a position of the throttle actuator, a speed sensor operable to provide a speed signal associated with the electric snowmobile, a user interface operable to receive a reverse request from a driver of the snowmobile, and a controller having a processor and a non-transitory memory, the non-transitory memory having instructions stored thereon, the instructions being executable by the processor for enabling the controller to: when the controller is in a drive state, operate an electric motor of the electric snowmobile in a forward angular direction based on the throttle signal, and, when the reverse request has been received, transition from the drive state to a reverse requested state; when the controller is in the reverse requested state, negate control of the electric motor on a basis of the throttle signal, and, transition to a reverse state when the speed signal transitions from above a speed threshold to below the speed threshold; and when the controller is in the reverse state, operate the electric motor in the reverse angular direction based on the throttle signal.

In some embodiments, the transitioning from the drive state to a reverse requested state is contingent upon determining that the throttle signal is below a throttle threshold value.

In some embodiments, the transitioning from the drive state to the reverse requested state includes changing an indicator configuration in the user interface of the electric snowmobile.

In some embodiments, the transitioning from the reverse requested state to the reverse state includes changing an indicator configuration in the user interface.

Embodiments may include combinations of the above features.

In a further aspect, the disclosure describes a method of transitioning an electric vehicle from a drive state to a reverse state, the method comprising: receiving at a controller a reverse request from a user interface of the electric vehicle; wherein, upon receipt of the reverse request, the controller being operative to: transition the electric vehicle from a drive state to a reverse state when a speed signal associated with the electric vehicle is below a predetermined speed threshold, wherein in the reverse state, the controller drives the electric vehicle in a reverse direction based on a throttle signal; and, transition the electric vehicle from a drive state to a reverse requested state when a speed signal associated with the electric vehicle is above a predetermined speed threshold, wherein in the reverse requested state, the controller does not drive operation of the electric vehicle based on the throttle signal.

In some embodiments, when the electric vehicle is in the reverse requested state, the controller is further operative to: transition the electric vehicle from the reverse requested state to the reverse state when the speed signal transitions from above the speed threshold to below the speed threshold.

In a further aspect, the disclosure describes a method of transitioning an electric snowmobile from a drive state to a reverse state, the method comprising: receiving at a controller a reverse request from a user interface of the electric snowmobile; wherein, upon receipt of the reverse request, the controller being operative to: transition the electric snowmobile from a drive state to a reverse state when a speed signal associated with the electric snowmobile is below a predetermined speed threshold, wherein in the reverse state, the controller drives an electric motor of the electric snowmobile in a reverse direction based on a throttle signal; and, transition the electric snowmobile from a drive state to a reverse requested state when a speed signal associated with the electric snowmobile is above a predetermined speed threshold, wherein in the reverse requested state, the controller drives the electric motor in a regenerative mode to actively decelerate the electric snowmobile.

In some embodiments, in the reverse requested state, the controller sustains the regenerative mode until the speed signal reaches the predetermined speed threshold.

Embodiments may include combinations of the above features.

Many further features and combinations thereof concerning the present improvements will appear to those skilled in the art following a reading of the instant disclosure.

DESCRIPTION OF THE FIGURES

In the figures,

FIG. 1 is a schematic side elevation view of an example electric vehicle including a power indicator as described herein;

FIG. 2 is a schematic representation of a user interface of the electric vehicle of FIG. 1;

FIG. 3 is another schematic representation of the electric vehicle of FIG. 1;

FIG. 4 is another schematic representation of the electric vehicle of FIG. 1 is another schematic illustration of the vehicle of FIG. 1;

FIG. 5 is a flow chart of a method of operating the electric vehicle of FIG. 1;

FIGS. 6A-6B are flow charts of methods of operating the electric vehicle of FIG. 1;

FIGS. 7A-7C provide an example of successive changes in an indicator configuration of a user interface corresponding to successive controller state transitions;

FIG. 8 shows a configuration of an example circuit of the electric vehicle of FIG. 1;

FIG. 9 is a flow chart presenting a method of determining power limits to the electric vehicle of FIG. 1.

DETAILED DESCRIPTION

The following disclosure relates to systems and associated methods for controlling the operation of electric vehicles. In some embodiments, the systems and methods described herein may be particularly suitable for electric powersport vehicles. Examples of suitable electric powersport vehicles include snowmobiles, all-terrain vehicles (ATVs), and (e.g., side-by-side) utility task vehicles (UTVs). In some embodiments, the systems and methods described herein may provide a relatively user-friendly forward to reverse transition sequence. In some embodiments, the systems and methods described herein may promote the operator's awareness of the state of the electric vehicle, facilitate human/machine interaction, and promote operator experience. In some embodiments, the systems and methods described herein may promote a safe operation of an electric vehicle by reducing a risk of the electric vehicle being inadvertently placed in a reverse state and/or being inadvertently caused to be propelled in a reverse direction.

Indeed, in addition to potentially limiting the torque or power output to appropriate levels, it can be desired for a controller of an electric snowmobile to prevent sudden reversals of torque or power output. However, traditional combustion engine based snowmobiles can typically be switched from forward to reverse via a mechanical transmission actuator independently of the movement of the vehicle in the forward direction, which some combustion engine snowmobile operators may have come to appreciate in some driving conditions. Accordingly, snowmobile operators accustomed to combustion engine snowmobiles who want to transition to an electric snowmobile, may not appreciate the experience of a controller which prevents them from switching to reverse while the vehicle is still moving. In some embodiments, such inconveniences may be alleviated by introducing an intermediary state, which may be referred to as a “reverse requested” state, into which the operator may transition the controller while the vehicle is still moving. In the intermediary state, the reverse operation of the motor can be prevented. The controller may be configured to automatically transition from the reverse requested state into a reverse state, based on detecting that the vehicle speed has transitioned from above to below a speed threshold. Once in the reverse state, reverse operation of the motor can be allowed based on the throttle signal. Indeed, this can allow the reverse request from the operator to be “remembered” by the controller until conditions are deemed appropriate for its execution.

The terms “connected” and “coupled” may include both direct connection and coupling (where two elements contact each other) and indirect connection and coupling (where at least one additional element is located between the two elements).

The term “substantially” as used herein may be applied to modify any quantitative representation which could permissibly vary without resulting in a change in the basic function to which it is related.

Aspects of various embodiments are described through reference to the drawings.

FIG. 1 is a schematic side elevation view of an exemplary electric snowmobile 10 (referred hereinafter as “vehicle 10”). As illustrated in FIG. 1, vehicle 10 may be a snowmobile but it is understood that controller and control methods described herein may also be used with other types of electric off-road vehicles including utility task vehicles (UTVs), such as side-by-side vehicles and all-terrain vehicles (ATVs) for instance.

Vehicle 10 may include a frame (also known as a chassis) which may include tunnel 14, track 16 having the form of an endless belt for engaging the ground and disposed under tunnel 14, one or more electric motors 18 (referred hereinafter in as “motor 18”) mounted to the frame and configured to drive track 16. The vehicle 10 may further include left and right skis 20 disposed in a front portion of vehicle 10, straddle seat 22 disposed above tunnel 14 for accommodating an operator of vehicle 10 and optionally one or more passengers. Skis 20 may be pivotally connected to the frame via a steering column interconnecting handlebar 24 with skis 20 to permit steering of vehicle 10 via a steering assembly including.

Motor 18 may be drivingly connected to track 16 via a drive shaft to cause propulsion of vehicle 10. Motor 18 may be in torque-transmitting engagement with the drive shaft via a belt/pulley drive. However, motor 18 may be in torque-transmitting engagement with the drive shaft via other arrangements such as a chain/sprocket drive, or shaft/gear drive for example. The drive shaft may be drivingly connected to track 16 via one or more toothed wheels or other means so as to transfer motive power from motor 18 to track 16.

Vehicle 10 may include a controller 28 and a throttle actuator 30. The controller 28 may include more than one control unit communicatively coupled to one another, one or more of which may be a computer. The operation of motor 18 may be controlled by the controller 28 based on an actuation of throttle actuator 30, i.e. accelerator, by the operator. More specifically, the throttle actuator 30 can generate a throttle signal which varies over time as a function of variations in the position of the throttle actuator 30. The controller 28 can have a function to map an amplitude of the throttle signal to a power request for the electric motor 18, and to control the electric motor based on the power request. The mapping of the amplitude of the throttle signal to the power request may be subject to a current operating mode of the controller 28. Vehicle may further include one or more sensors 34 for sensing one or more operating parameters of vehicle 10. The power request communicated to the electric motor 18 may further be based on feedback from one or more sensors 34.

Vehicle 10 may also include one or more batteries 26 (referred hereinafter in the singular as “battery 26”) for providing electric power to motor 18 and driving motor 18. Battery 26 may be a main battery pack used for propelling vehicle 10, and may be referred to as a motoring battery. Battery 26 may be disposed under seat 22. In some embodiments, battery 26 may be a rechargeable lithium ion or other type of battery. In some embodiments, battery 26 may be configured to output electric power at a voltage of between 300-400 volts, or up to 800 volts, for example. The controller 28 can have a function to control the delivery of electrical power from the battery 26 to the electric motor 18. Vehicle may further include a utility battery, e.g. 12 volt battery, configured for powering the controller and any electrically powered accessories of the vehicle 10, but not the motor 18.

Vehicle 10 may also include one or more brakes (referred to below in the singular) that may be applied or released by an actuation of a suitable brake actuator (e.g., brake lever 31 presented in FIG. 2) by the operator for example. Brake may be operable as a main brake for the purpose of slowing and stopping vehicle 10 during motion of vehicle 10. Alternatively or in addition, brake may be operable as a parking brake, sometimes called “e-brake” or “emergency brake”, of vehicle 10 intended to be used when vehicle 10 is stationary. In various embodiments, such main and parking brake functions may use separate brakes, or may use a common brake. For example, brake may have a friction-type brake including a master cylinder operatively connected to a brake calliper that urges bake pads against a brake rotor or disk that is coupled to the powertrain of vehicle 10. In some embodiments, such brake rotor may be secured to and rotatable with drive shaft of motor 18.

Actuation of the brake actuator (e.g. lever 31) may cause one of, or both, tractive braking and regenerative braking. Regenerative braking can be controlled via controller 28. In some embodiments, regenerative braking may be used such that the battery 26 is supplied with electric energy generated by motor 18 operating as a generator when the brake actuator (e.g. lever) is applied, and/or when the operator releases throttle actuator 30. Such torque operating in a direction contrary to the current direction of movement of the vehicle in decelerating the vehicle can be referred to as negative torque.

In some embodiments, system 12 may include an operator key (not shown) permitting the operation of vehicle 10 when key is received into receptacle of vehicle 10, or when key is in sufficient proximity to vehicle 10 for example. The engagement of key with receptacle or the proximity of key to vehicle 10 may be communicated to controller 28 so that controller 28 may authorize the operation of vehicle 10. Key may be attached to one end of tether (e.g., lanyard). The opposite end of tether may be attached to the vehicle operator's clothing or belt during operation of vehicle 10. The use of tether and key may allow system 12 to automatically stop propulsion of vehicle 10 by, for example, shutting down or reducing the output of motor 18 to prevent vehicle runaway in an emergency situation such as where the operator would become separated from vehicle 10 and consequently key would become removed from receptacle for example. In some embodiments, separation of the key from the receptacle may prevent vehicle runaway in an emergency situation by preventing propulsion of vehicle 10 and/or activating (e.g. regenerative) braking of motor 18.

Vehicle 10 may include a user interface 32 which can include one or more buttons (e.g. a button cluster), and one or more visual indicators. Visual indicators can be embodied in physical devices such as needle indicators, gauges, dials and digital readouts, and/or as virtual devices such as virtual needle indicator, gauges, dials, and digital readouts represented as corresponding elements of a graphical user interface on a display screen or touch screen. Similarly, buttons can be embodied as physical (hardware) devices such as movable press buttons in a button cluster which trigger electrical contacts, or as virtual devices involving both hardware and software, such as portions of a touch screen delimited by graphical elements displayed when the screen is powered. The user interface 32 may include a liquid crystal display (LCD) screen, thin-film-transistor (TFT) LCD screen, light-emitting diode (LED), a button cluster, or other suitable display device operatively connected to controller 28 and/or to one or more other systems of vehicle 10.

In an embodiment, the user interface 32 can include a graphical user interface 33 displayed on a display screen such as presented in FIG. 2. The graphical user interface 33 can be configured for displaying some or all of the values measured by sensors 34 to a user. The graphical user interface may include a speedometer 35 indicating a current speed of vehicle based on a speed sensor. In this embodiment, the speedometer 35 is embodied as a digital readout. The graphical user interface 33 can further include a tachometer 49 indicating a current angular rotation speed of motor 18 in revolutions-per-minute (RPM), including in an embodiment both a digital readout and a virtual dial, a power indicator indicating an amount of power being generated by a powertrain of vehicle 10, including in an embodiment both a digital readout and a virtual dial, a battery state of charge (SoC) indicator 41 associated with battery 26, and/or other indicators such as analog or digital readouts, based on corresponding sensors. In particular, controller operating mode indicators (e.g. “Eco”, “Normal” and “Sport”) can be provided in this example at a top portion of the display screen, and controller drive state (e.g. Drive “D”, Neutral “N”, Reverse “R”) indicator can be provided at a bottom portion of the display screen. One or more of the elements of the graphical user interface 33 can have variable colors. The controller can be said to change an indicator configuration of the user interface 33 when changing either one, or more than one of the operating mode indicator, a controller drive state indicator, and/or a variable color of one or more elements of the graphical user interface 33.

In an embodiment, the user interface 32 further includes a plurality of user inputs (e.g. buttons, dials, switches, toggles, levers, etc.). In one embodiment, the user inputs can be embodied as hardware buttons and can include a button cluster 45 disposed on a left handlebar adjacent a brake lever 31 and an emergency stop button 43 disposed on a right handlebar adjacent a throttle actuator 30. The button cluster can include a reverse/forward button 47 and additional buttons. Additional user inputs can be provided to allow a user to change between controller operating modes such as driving modes (e.g. Sport, Eco, etc.), regenerative braking modes (e.g. regen off, low regen, high regen), handlebar heating activation and headlight activation, among other possibilities. Changes stemming from user input can be reflected in corresponding portions of the graphical user interface. In an embodiment, the user interface 32 further includes an audible indicator including a speaker.

Referring to FIG. 3, a schematic diagram of components of vehicle 10 is shown. The vehicle 10 has a propulsor 2 (e.g. track 16). At least one electric motor 3 (e.g. motor 18) is drivingly engaged to the propulsor 2 and operatively connectable to a power source 5 (e.g. battery 26). At least one input device 6 (e.g. throttle actuator 30) is operatively connected to the electric motor 3. The electric motor 3 has a forward configuration in which a motor output 4 (e.g. a rotor) of the electric motor 3 rotates in a first direction R1. The electric motor 3 has a rearward configuration in which the motor output 4 of the electric motor 3 rotates in a second direction R2 opposite the first direction R1. The input device 6 is engageable to operate the electric motor 3 in a selected one of the forward configuration and the rearward configuration. In the forward configuration, the motor output 4 of the electric motor 5 engages the propulsor 2 in such a way that the propulsor 2 propels the vehicle 10 in a forward direction D1. In the rearward configuration, the motor output 4 of the electric motor 3 engages the propulsor 2 in such a way that the propulsor 2 propels the straddle seat vehicle 10 in a rearward direction D2 opposite the forward direction D1 (also represented relative the vehicle in FIG. 1).

FIG. 4 is another schematic representation of vehicle 10. Motor 18 may provide propulsive power to vehicle 10 and may be part of powertrain 36 of vehicle 10. In various embodiments, motor 18 may be a permanent magnet synchronous motor or a brushless direct current motor for example.

Motor 18 may be drivingly connected to track 16 (shown in FIG. 1) in embodiments where vehicle 10 is a snowmobile for example. For UTVs and ATVs, motor 18 may be drivingly connected to ground-engaging wheels. Powertrain 36 may also include battery 26 for providing electric power to motor 18. The operation of motor 18 and the delivery of electric power to motor 18 may be controlled by controller 28 via output(s) 37 and power electronics module 38 (referred hereinafter as “PEM 38”). PEM 38 may include suitable electronic switches (e.g., insulated gate bipolar transistor(s)) to provide motor 18 with electric power having the desired voltage, current, waveform, etc. to implement the desired performance of vehicle 10 based on an actuation of throttle actuator 30 by the operator to indicate a command to propel vehicle 10A. In some embodiments, PEM 38 may include a power inverter for example.

One or more of sensors 34 may be operatively connected to component(s) of powertrain 36 and configured to sense one or more parameters of powertrain 36. Controller 28, via the control of PEM 38 and using feedback from sensor(s) 34, may control the amount of motive power that may be output from powertrain 36 during propulsion of vehicle 10, and also control the amount of electric power that may be delivered to battery 26 during regenerative braking. Controller 28 may include one or more data processors 40 (referred hereinafter as “processor 40”) and non-transitory machine-readable memory 42. Controller 28 may be operatively connected to sensor(s) 34 via wired or wireless connections for example so that one or more parameters acquired via sensor(s) 34 may be received at controller 28 and used by processor 40 in one or more procedures or steps defined by machine-readable instructions 44 stored in memory 42 and executable by processor 40.

Controller 28 may carry out additional functions than those described herein. Processor 40 may include any suitable device(s) configured to cause a series of steps to be performed by controller 28 so as to implement a computer-implemented process such that instructions 44, when executed by controller 28, may cause the functions/acts to be executed.

Processor 40 may include, for example, any type of general-purpose microprocessor or microcontroller, a digital signal processing (DSP) processor, an integrated circuit, a field programmable gate array (FPGA), a reconfigurable processor, other suitably programmed or programmable logic circuits, or any combination thereof.

Memory 42 may include any suitable machine-readable storage medium. Memory 42 may include non-transitory computer readable storage medium such as, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. Memory 42 may include a suitable combination of any type of machine-readable memory that is located either internally or externally to controller 28. Memory 42 may include any storage means (e.g. devices) suitable for retrievably storing machine-readable instructions executable by processor 40.

Sensor(s) 34 may include one or more current sensors and/or one or more voltage sensors operatively connected to battery 26 and/or operatively connected to PEM 38. Sensor(s) 34 may include a position sensor (e.g., encoder) operatively coupled to motor 18 to measure a position and/or rotational speed of a rotor of motor 18. Sensor(s) 34 may include a speed sensor (e.g., revolution counter) operatively coupled to motor 18 to measure the rotational speed of motor 18 and generate a speed signal indicative of a current rotation speed of the electric motor as it changes over time. Sensor(s) 34 may include a torque sensor operatively coupled to motor 18 to measure an output torque of motor 18. Alternatively, the output torque of motor 18 may be inferred by controller 28 based on an amount of electric current being delivered to motor 18. Sensor(s) 34 may include one or more temperature sensors such as one or more thermocouples or resistance temperature detectors (RTD) suitable for measuring a temperature of one or more cells of battery 26, and/or for measuring a temperature of a component of motor 18 for example. Sensor(s) 34 may acquire one or more signals indicative of, or useful in inferring, one or more operating parameters 46 of powertrain 36. For example, sensor(s) 34 may acquire one or more signals indicative of, or useful in inferring, an amount of electric power being discharged from battery 26 during propulsion of vehicle 10, an amount of electric power being received into battery 26 to charge battery 26 during regenerative braking of vehicle 10, an amount of motive power being generated by motor 18 during propulsion of vehicle 10, and/or an amount of electric power being generated by motor 18 when motor 18 is operating as a generator during regenerative braking of vehicle 10. Sensor(s) 34 may acquire one or more signals indicative of, or useful in inferring, a state of charge (SoC) of battery 26 and/or other parameters of powertrain 36. The SoC may be expressed as a percentage of the capacity of battery 26 (e.g., 0%=empty; 100%=full), or as any other suitable indication. Sensor(s) 34 may include one or more potentiometers for obtaining a throttle signal indicative of a position of throttle actuator 30, and/or obtaining a brake signal indicative of a position of a brake lever 31, for instance. In an alternative embodiment, sensor(s) 34 may include one or more limit switches for sensing activation of brake lever 31.

The throttle actuator 30 may be operatively connected (e.g. in electronic communication, wired) to controller 28 so that controller 28 may control some aspects of operation of the powertrain 36 based on instructions 44. For example, the throttle actuator 30 may be a source of a throttle (i.e. acceleration) signal which can vary over time based on changes in a position of a throttle actuator 30. The change can be a change in amplitude or a change in a frequency of the throttle signal for instance. The controller 28 can map a given value of the throttle signal to a given power request from the motor 18 based on the instructions. The mapping may be constant throughout operating conditions, or various mappings can be defined in the instructions 44 and be adapted to different driving modes or driving conditions. For instance, a sports mode mapping may be defined as more aggressively mapping smaller changes in the throttle signal to larger changes in requested power, whereas an eco mode mapping may be defined as less aggressively mapping corresponding changes in the throttle signal to smaller changes in requested power. More than two driving modes, and associated mappings, may be provided for. The controller 28 can be configured to allow the operator to switch from one driving mode to another via one or more elements of the user interface 32, such as switching buttons and a visual indication of the current state for instance. The mapping may be the same, or different, between forward and reverse states of operation, with a significant difference being that the motor 18 can be driven to rotate in different orientations between the forward and reverse states of operation.

User interface 32 may be operatively connected (e.g., in electronic communication, wired) to controller 28 so that controller 28 may control some aspects of operation of user interface 32 or of the power electronics module 38 based on instructions 44. For example, based on one or more sensed parameters 46 of powertrain 36, controller 28 may determine, based on limits data 48, whether or not the operation of vehicle 10 needs to be restricted to mitigate a non-normal operating condition or for another reason. The limits data 48 may be used to identify an available power limit based on the operating conditions determined by the sensed parameters 46 at a given time. The available power limit may vary over time as the operating conditions of the vehicle 10 change. Controller 28 may be configured to restrict operation of vehicle 10 based on limits data 48 and also cause user interface 32 to visually display one or more applied limits. Such one or more applied limits may limit the power request outputted from the controller 28 to the powertrain 36. For instance, if the power request determined from the mapping of the throttle signal is lower than the one or more applied limits, the mapped power request can be directly outputted from the controller 28 to the powertrain 36, whereas if the mapped power request is greater than the one or more applied limits, the power request outputted from the controller 28 to the powertrain 36 may be reduced compared to the mapped power request based on the one or more limits. The power request outputted from the controller 28 to the powertrain 36 can be executed via the power electronics module 38 which can control an amount of power delivered to the motor from the batteries 26. In an alternate embodiment, the power electronics module 38 can be considered to form part of controller 28.

The drive state can be defined as a mode of operation in which the electric motor 18 will be controlled in a manner to drive in a forward direction D1 of the vehicle 10. In a direct drive configuration, rotating the electric motor 18 in a forward angular direction R1 drives the electric snowmobile 10 in a forward direction D1, and rotating the electric motor 18 in a rear angular direction R2 drives the electric snowmobile 10 in the rear direction D2. Similarly, the reverse state can be defined as a mode of operation in which the electric motor 18 will be driven in a rear angular direction R2 corresponding to a rear direction D2 of the vehicle 10.

Presented in FIG. 5, is a method 102 of controlling the vehicle 10. Broadly stated, controller 28 may map (block 90) the throttle signal 92 to a power request 96 at least in part on a basis of a power map 94, and subsequently control (block 98) the electric motor 18 based on the power request 96. Power map 94 may vary depending on a vehicle drive mode (Eco, Normal, Sport) as well as depending on whether the vehicle 10 is in drive state vs. a reverse state, for example. Controller 28 may enable changing of the power map 94 during operation of the vehicle 10, such as upon operator intervention such as by interacting with user interface 32 (e.g. switching drive mode between Eco, Sport, etc,) or automatically (e.g. by providing a different map for the reverse state than for the drive state). In some embodiments, in the reverse state, the mapping between the throttle signal 92 and the power request 96 can be different, or the same, than in the drive state.

Upon determination of the power request 96, controller 28 may determine (decision block 160) whether the value of the power request 96 is above an available power limit. As described above, the available power limit may be determined based on the limits data 48 and the operational condition of the vehicle 10 as determined based on sensed parameters 46. If the value of the power request 96 is above the available power limit, the power request 96 may be set (block 162) to the available power limit before being applied to control the electric motor 18 (block 98). If the value of the power request 96 is below the available power limit, the power request 96 may be directly applied to control the electric motor 18 (block 98). The power request 96 is thus applied to the powertrain by the controller 28 to control propulsion of the vehicle.

The method 102 presented in FIG. 5 may be adapted to both operation in the drive state and to operation in the reverse state. The power request 96 may be applied to the powertrain by controller 28 to drive the propulsion of the vehicle in both the forward direction D1 and the rear direction D2.

Turning now to FIG. 6A, an example method 100 of transitioning between a drive state (forward operation) and a reverse state is presented. Prior to receiving a reverse request, controller 28 maintains vehicle 10 in the drive state (block 104), such as by executing method 102 described in FIG. 5, for example. While in the drive state, controller 28 determines (decision block 106) whether a reverse request has been received. A reverse request may be received via the forward/reverse button 47 of user interface 32, for example, or another user input. A reverse request may be received based on a short press activation of the forward/reverse button 47, or alternatively a long press (e.g. 2 or more seconds) of the forward/reverse button 47. In an alternate embodiment, forward/reverse button 47 may mechanically remain depressed following activation and generate the reverse request until it is pressed again to revert to its initial state. So long as a reverse request is not received, controller 28 maintains vehicle 10 in the drive state (block 104).

If controller 28 determines that a reverse request has been received, controller 28 may verify that the throttle signal is below a given throttle threshold (block 108). In some embodiments, this may be an optional step. The throttle threshold may correspond to a position of the throttle actuator 30, such as less than 3% or 5% of an actuation range of throttle actuator 30, for example. In some embodiments, the throttle threshold may be substantially 0, such that method 100 does not proceed towards transitioning from the drive state to the reverse state unless the throttle actuator 30 is in a zero position (i.e. un-actuated). This verification may be performed as a safety check to ensure that the forward/reverse button 47 was not pressed inadvertently. If a throttle signal from throttle actuator 30 is above the throttle threshold (e.g. the throttle actuator 30 is being actuated) when a reverse request is received (e.g. forward/reverse button 47 is actuated), then the reverse request may be ignored and vehicle 10 is caused to maintain the drive state (block 104).

Upon receipt of the reverse request and any additional conditions being satisfied, such as the optional condition of the throttle signal being below the throttle threshold, controller 28 determines whether a speed signal from the vehicle is below a predetermined speed threshold (decision block 110). A sudden transition of direction at speeds above the threshold may be undesirable in a snowmobile. It is preferable to dampen a transition between directions to prevent harm to an operator and/or damage to the vehicle. More particularly, it may be damaging to components of the powertrain for the vehicle 10 to transition from a drive state to a reverse state when motor 18 is rotating in the forward angular direction R1 at relatively high speeds. Controller 28 may thus prevent motor 18 and/or vehicle 10 from switching to the reverse state when one or both of the motor speed and/or the vehicle speed are above a predetermined speed threshold in the forward direction. A speed check against the predetermined speed threshold is performed before allowing the vehicle 10 to transition from a drive state to a reverse state (decision block 110).

In one embodiment, the speed signal associated with vehicle 10 received at controller 28 may be indicative of a motor speed (rpm). In another embodiment, the speed signal associated with vehicle 10 received at controller 28 may be indicative of a vehicle speed. The vehicle speed may be determined from a Global Positioning System (GPS), for example, or alternatively may be inferred or calculated from a motor speed (rpm). For example, in an electric snowmobile 10 having a direct drive configuration, a rotation speed (rpm) of electric motor 18 can be considered suitably proportional to vehicle speed to enable vehicle speed to be derived, calculated, or inferred.

In accordance with some non-limiting examples, the speed threshold for vehicle speed may be in the order of 1, 2 or 5 km/h, for example, but other values, including values above or below these examples, may be preferred in alternate embodiments. In accordance with some non-limiting examples, the speed threshold for motor speed (rpm) may be between 30 and 250 RPM, such as less than or approximately 30 RPM, 60 RPM, 100 RPM, 150 RPM or 250 RPM for instance, but other values, including values above or below this range may be preferred in alternative embodiments. In some examples, the speed threshold may be configurable and/or selectable by an operator, while being constrained within certain safety limits. Furthermore, a ramp down rate of the motor speed and/or vehicle speed towards the predetermined speed threshold may also be user selectable and configurable. The speed threshold and ramp down rate may be different for each of the vehicle drive modes (e.g. Eco, Normal, Sport).

While it may be undesirable to transition from the drive state to the reverse state when vehicle 10 is operating at relatively high speeds, it may also be undesirable to require that an operator waits until vehicle 10 and/or motor 18 have come to a complete stop before allowing an operator to convey their desire to transition directions. Accordingly, it may be desirable to allow an operator to provide a reverse request (e.g. press the reverse button 47) even while the vehicle is in motion and operating at high speeds. However, upon receipt of the reverse request, the actual transition from the drive state to the reverse state should be avoided until a speed signal is below the speed threshold. In such cases, controller 28 may place vehicle 10 into an intermediate state for a time period between receiving a reverse request and vehicle 10 and/or motor 18 achieving a speed at or below the speed threshold. This intermediate state may serve the function of enabling controller 28 to override any throttle signal to zero so that vehicle 10 is forced to slow down to below the speed threshold before vehicle 10 enters the reverse state (i.e. before the reverse state is activated).

Accordingly, upon receipt of the reverse request, controller 28 determines if the speed signal received is below the speed threshold (decision block 110). If the speed signal is indicative that the speed of the motor 18 and/or vehicle 10 is below the speed threshold, controller 28 transitions vehicle 10 to a reverse state (block 112). As such, if the reverse request is received when vehicle 10 is stationary or operating at a suitably low speed (i.e. below the speed threshold), controller 28 transitions vehicle 10 directly to the reverse state (block 112) such that subsequent operation of throttle actuator 30 will cause motor 18 to rotate in the rear angular direction R2 such that vehicle 10 is propelled in the reverse direction D2.

However, if the speed signal is indicative that the speed of motor 18 and/or vehicle 10 is above the speed threshold, controller 28 transitions vehicle 10 to an intermediate, reverse requested state (block 114). In other words, if the reverse request is received when vehicle 10 is operating at a relatively fast speed (i.e. above the speed threshold), where abrupt transition between states could be undesirable to an operator and/or cause damage to vehicle components, controller 28 transitions vehicle 10 to an intermediate, reverse requested state.

The reverse requested state provides an intermediate state where vehicle 10 is enabled to slow down to acquire an operational condition where controller 28 can transition vehicle 10 to the reverse state safely. Accordingly, in one embodiment, while in the reverse requested state, controller 28 may not accept throttle signals 92 received from throttle actuator 30 for controlling motor 18. In other words, controller 28 ignores throttle signals 92 received from throttle actuator 30 while vehicle 10 is in the reverse requested state. In still other words, controller 28 overrides any throttle signal 92 to zero while in the reverse requested state. As such, an operator is prevented from accelerating vehicle 10, so as to enable vehicle 10 and/or motor 18 to reduce speed to below the speed threshold.

In an alternative embodiment, actuation of the throttle actuator 30 during the intermediate, reverse requested state causes the reverse request to be voided, and controller 28 returns vehicle 10 to the drive state.

In the reverse requested state, controller 28 may provide an operator-perceptible indication (e.g. indicator scheme) to the operator via the user interface 33, to clearly convey to an operator that vehicle 10 is in the reverse requested state. This indication to the operator may be distinguishable from the drive state and/or distinguishable from the reverse state. Such user feedback may improve user experience by conveying to the operator the current operational condition of the vehicle. In this manner, the operator will not expect actuation of throttle actuator 30 to generate propulsion, thereby avoiding puzzlement and frustration. In one embodiment, such an indication can include changing a color of one or more portions of the graphical user interface 33 in a manner to produce a noticeable change compared with the previous state, e.g. the drive state. In one embodiment, one or more portions of the graphical user interface 33 may be switched to a different color in the reverse requested state than the color used in the drive state or the reverse state. In one embodiment, such an indication can include activating an audible indication such as a repeating beep. The one or more changes can reflect a difference between an indicator scheme of the drive state and an indicator scheme of the reverse state.

While the vehicle is in the reverse requested state, controller 28 may continuously and/or intermittently monitor the speed signal (block 110), such that when vehicle 10 and/or motor 18 drop to speeds below the speed threshold, controller 28 transitions vehicle 10 to the reverse state (block 112). In other words, controller 28 maintains vehicle 10 in the reverse requested state while the vehicle speed is above the speed threshold (block 114) and transitions vehicle 10 to the reverse state when the speed signal drops below the speed threshold (block 112). Controller 28 may monitor the speed signal in a manner to affect the transition when the speed signal transitions from above the speed threshold to below the speed threshold.

Depending on the embodiment, one or more timers may be used as a basis for one or more additional conditions. For instance, a first timer may be activated upon transitioning into the reverse requested state (block 114) and when the first timer reaches a first time limit, controller 28 may automatically transition from the reverse requested state back to the drive state if the speed signal has not been reduced below the speed threshold within the first time limit. In some embodiments, controller 28 may also transition back into the drive state if a drive request is received. In an embodiment, the drive request can be identical to the reverse request (i.e. an input received from pressing of a forward/reverse button 47 by the operator). As another example, a timer can be activated upon determining that the speed is already below the speed threshold at an initial check (block 110), and the controller 28 may delay the transition into the reverse state based on reaching a predetermined time limit.

In an embodiment, controller 28 may trigger an operator-perceptible indication (e.g. indicator scheme) in the user interface 33 upon the transition to the reverse state, which can signify to the operator that activation of the throttle actuator 30 will now lead to delivering rearward acceleration. In an embodiment, the indication in the user interface 33 may include a further change in a color of one or more portions of the graphical user interface 33. Alternatively, or in addition, the indication may include a perceptible change in an audible signal (e.g. change a frequency of an audible beep). In an embodiment, the indication to the operator corresponding to the reverse state can be distinguishable from both the indication corresponding to the drive state and the indication corresponding to the reverse requested state.

In some embodiments, additional functions may be triggered when in the reverse requested state. For instance, in an embodiment, when in the reverse requested state, controller 28 may change a mode of operation of the electric motor 18 to a zero-torque mode, where controller 28 commands the motor 18 to acquire a zero torque state (i.e. a no-load operating state). In other words, the no-load operating state may correspond to substantially no torque being output from motor 18 or being input into motor 18 operating as a generator. As motor 18 is operated at no load, the total input power to motor 18 may be relatively low and substantially equal to (e.g., iron, friction and windage) losses of motor 18.

Alternately, when in the reverse requested state, controller 28 may change a mode of operation of the electric motor 18 to a regenerative mode where motor braking is applied (negative torque relative the direction of movement) to reduce the vehicle speed more quickly than it would reduce in a zero torque scenario. In the regenerative mode, electric power generated by motor 18 is provided to battery 26. In one embodiment, the regenerative mode can be sustained until one or more conditions are met, such as until the speed signal reaches or goes below the speed threshold for instance. Various alternatives exist in ways to embody a regenerative mode, one of which is to control negative torque in a manner to lead to a target power recovery value corresponding, for example, with a recharging capacity of the battery 26. Other ways to embody a regenerative mode specific to a reverse requested state may be to limit the amount of regenerative braking to a different value below the recharging capacity of the battery 26. In still another embodiment, in the reverse requested state, the throttle signal and/or the brake signal may be mapped by controller 28 to a negative value of torque (i.e. a value of regenerative braking).

Turning now to FIG. 6B, an example method 120 of transitioning between the reverse state and the drive state (forward operation) is presented. Prior to receiving a forward request, controller 28 maintains vehicle 10 in the reverse state (block 122). While in the reverse state, controller 28 determines (decision block 124) whether a forward request has been received, or in alternative embodiments, whether a reverse request has ceased to be received. A forward request may be received via the reverse/forward button 47 of user interface 32, for example, or another user input. A forward request may be received based on a short press activation of the reverse/forward button 47, or alternatively a long press (e.g. 2 or more seconds) of the reverse/forward button 47., So long as no forward request is received, controller 28 maintains vehicle 10 in the reverse state (block 122).

In an alternative embodiment, if while in the reverse state the vehicle 10 is turned “off”, the vehicle 10 may default back to the drive state (forward operation) when it is turned back “on”. In a further alternative embodiment, if while in the reverse state the vehicle 10 is put into an “awake” state where it is “on” but does not respond to throttle signals from throttle actuator 30, vehicle 10 may default back to the drive state when it is returned to an “active” state where the controller 28 responds to throttle signals from throttle actuator 30 to propel vehicle 10.

Returning to FIG. 6B, if controller 28 determines that a forward request has been received, controller 28 may optionally verify that the throttle signal is below a given throttle threshold (block 126). The throttle threshold may correspond to a position of the throttle actuator 30, such as less than 3% or 5% of actuation range of throttle actuator 30, for example. In some embodiments, the throttle threshold may be substantially 0, such that method 120 does not proceed towards transitioning from the reverse state to the drive state unless the throttle actuator 30 is in a zero position (i.e. un-actuated). This verification may be performed as a safety check to ensure that the reverse/forward button 47 was not pressed inadvertently. If a throttle signal from throttle actuator 30 is above the throttle threshold (e.g. the throttle actuator 30 is being actuated) when a forward request is received (e.g. reverse/forward button 47 is actuated), then the forward request may be ignored and vehicle 10 is caused to maintain the reverse state (block 122).

Upon receipt of the forward request and any additional conditions being satisfied, such as the optional condition of the throttle signal being below the throttle threshold, controller 28 determines whether a speed signal from the vehicle is below a predetermined speed threshold (decision block 128).

The speed threshold for transitioning from the reverse state to the drive state may be the same or different than the speed threshold for transitioning form the drive state to the reverse state, as described above. In some embodiments, the speed threshold for transitioning from the reverse state to the drive state may be the less than the speed threshold for transitioning form the drive state to the reverse state.

While it may be undesirable to transition from the reverse state to the drive state when the vehicle is operating at relatively high speeds, it may also be undesirable to require that an operator waits until vehicle 10 and/or motor 18 have come to a complete stop before allowing an operator to convey their desire to transition directions. Accordingly, it may be desirable to allow an operator to provide a forward request (e.g. press the reverse/forward button 47) even while vehicle 10 and/or motor 18 is in motion and operating at high speeds. However, upon receipt of the forward request, the actual transition from the reverse state to the drive state should be avoided until a speed signal is below the speed threshold.

Accordingly, upon receipt of the forward request, the controller determines if the speed signal received is below the speed threshold (decision block 128). If the speed signal is indicative that the speed of motor 18 and/or vehicle 10 is below the speed threshold, the controller transitions vehicle 10 to a drive state (block 134). In other words, if the forward request is received when vehicle 10 is stationary or operating at a suitably low speed (i.e. below the speed threshold), controller 28 transitions vehicle 10 directly to the forward state (block 134) such that subsequent operation of throttle actuator 30 will cause motor 18 to rotate in the forward angular direction R1 such that vehicle 10 is propelled in the forward direction D1.

However, if the speed signal is indicative that the speed of the motor 18 and/or vehicle 10 is above the speed threshold, the controller transitions vehicle 10 to an intermediate, forward requested state (block 130). In other words, if the forward request is received when the vehicle 10 is operating at a relatively fast speed (i.e. above the speed threshold), where abrupt transition between states could be undesirable to an operator and/or cause damage to vehicle components, controller 28 transitions vehicle 10 to the intermediate, forward requested state.

The forward requested state provides an intermediate state where vehicle 10 is enabled to slow down to acquire an operational condition where controller 28 can transition vehicle 10 to the forward state safely. Accordingly, in one embodiment, while in the forward requested state, controller 28 may not accept throttle signals 92 received from throttle actuator 30 for controlling motor 18. In other words, controller 28 ignores throttle signals 92 received from throttle actuator 30 while in the forward requested state. As such, an operator is prevented from accelerating vehicle 10, so as to enable vehicle 10 and/or motor 18 to reduce speed to below the speed threshold.

In an alternative embodiment, actuation of the throttle actuator 30 during the intermediate, forward requested state causes the forward request to be voided, and controller 28 returns vehicle 10 to the reverse state.

While in the forward requested state, controller 28 may provide an operator-perceptible indication (e.g. indicator scheme) to the operator, via the user interface 33, to clearly convey to an operator that vehicle 10 is in the forward requested state. This indication to the operator may be distinguishable from the drive state and/or distinguishable from the reverse state. Such user feedback may improve user experience by conveying to the operator the current operational condition of the vehicle. In this manner, the operator will not expect actuation of the throttle actuator 30 to generate propulsion, thereby avoiding puzzlement and frustration. In one embodiment, such an indication can include changing a color of one or more portions of the graphical user interface 33 for instance, in a manner to produce a noticeable change compared with the previous state, e.g. the reverse state. In one embodiment, one or more portions of the graphical user interface 33 may be switched to a different color in the forward requested state than the color used in the drive state or the reverse state. In one embodiment, such an indication can include activating an audible indication such as a repeating beep. The one or more changes can reflect a difference between an indicator scheme of the drive state and an indicator scheme of the reverse state.

The operator-perceptible indication that the vehicle 10 is in the forward requested state may be the same or different than the operator-perceptible indication that the vehicle is in the reverse requested state.

While the vehicle is in the forward requested state, controller 28 may continuously and/or intermittently monitor the speed signal (block 128), such that when vehicle 10 and/or motor 18 speed drops below the speed threshold, controller 28 transitions vehicle 10 to the drive state (block 134). In other words, controller 28 can maintain the vehicle in the forward requested state while the vehicle speed is above the speed threshold (block 130) and transition vehicle 10 to the drive state when the speed signal transitions to below the speed threshold (block 134). Controller 28 may monitor the speed signal in a manner to affect the transition when the speed signal transitions from above the speed threshold to below the speed threshold.

Depending on the embodiment, one or more timers may be used as a basis for one or more additional conditions. For instance, a first timer may be activated upon transitioning into the forward requested state (block 130) and when the first timer reaches a first time limit, controller 28 may automatically transition from the reverse requested state back to the reverse state if the speed signal has not been reduced below the speed threshold within the first time limit. As another example, a timer can be activated upon determining that the speed is already below the speed threshold at an initial check (block 128), and the controller 28 may delay the transition into the drive state based on reaching a predetermined time limit.

In an embodiment, controller 28 may trigger an operator-perceptible indication (e.g. indicator scheme) in the user interface 33 upon the transition to the drive state, which can signify to the operator that activation of the throttle actuator 30 will now lead to delivering forward acceleration. In an embodiment, the indication in the user interface 33 may include a further change in a color of one or more portions of the graphical user interface 33. Alternatively, or in addition, the indication may include a perceptible change in an audible signal (e.g. change a frequency of an audible beep). In an embodiment, the indication to the operator corresponding to the drive state can be distinguishable from both the indication corresponding to the reverse state and the indication corresponding to the forward requested state.

FIGS. 7A, 7B and 7C present one of numerous possible examples of a change in an indicator scheme between different drive states. In this example, FIG. 7A presents a graphical user interface 33 in a first indicator scheme when the controller is in a drive state. The first indicator scheme includes illustrating various display items (e.g. the numerical values of motor speed (RPM) 49, vehicle speed (kph) 35 and motor power 39) in a first color, e.g. green, and providing a circle around the D to indicate the drive state. FIG. 7B presents a second indicator scheme corresponding to the reverse requested state. In the reverse requested state, various display items (e.g. the numerical values of motor speed 49, vehicle speed 35 and motor power 39) can appear in a second color, e.g. grey or purple. At this stage, the circle around the D can have disappeared such as illustrated, or remain around the D to name an example variant. Optionally, or additionally, an audible indicator can be activated in parallel. FIG. 7C presents a third indicator scheme corresponding to the reverse state. In the reverse state, various display items (e.g. the numerical values of motor speed 49, vehicle speed 35 and motor power 39) can remain in the second color as illustrated, or change to yet another color, e.g. orange, to name a possible variant. At this stage, the circle can appear around the R to indicate the reverse state. Optionally, or additionally, an audible indicator can be activated or, if it was already activated in the reverse requested state, it can be perceptibly changed such as by changing its pitch or frequency.

In yet another embodiment, a change of indicator scheme can include a change in a background color as opposed to a change in a display item. In yet another embodiment, instead of a change of color, the different indicator schemes may provide a change of texture, pattern or emphasis of various display items or backgrounds. In one embodiment, in the reverse requested state (and/or forward requested state), a separate icon, text message, or graphical indication may appear on the graphical user interface 33 covering various display items, such as one or all of the numerical values of motor speed 49, vehicle speed 35 and motor power 39 either partially or completely. The icon, text message or graphical indication may make clear to an operator that a reverse or forward requested state has been entered and that functioning of the throttle actuator 30 may be temporarily unavailable.

FIG. 8 shows an exemplary circuit 83 for activating vehicle 10. PEM 64 may be a non limiting example of Power Electronics Module 38 shown in FIG. 4. As shown, PEM 64 may be operatively connected between HV battery 26 and motor 18 to control the delivery of electric power from HV battery 26 to motor 18. Motor 18 may be a polyphase (e.g., 3-phase) synchronous motor and may include a plurality of armature (e.g., stator) windings such as armature windings L1, L2, L3. Armature windings L1, L2, L3 may be connected in a wye or delta configuration. Neutral point N may be connected to ground G.

PEM 64 may include inverter 84 and capacitor 82. Capacitor 82 may be electrically connected in parallel with inverter 84. Capacitor 82 may be a smoothing capacitor within PEM 64. Circuit 83 may also include fuse 86 operative to provide overcurrent protection for circuit 83.

In preparation for propulsion of vehicle 10, switches 65A and 65B are closed so that HV battery 26 can deliver electric power to motor 18. Switches 65A-65B may be operatively connected to be controlled via controller 28. In some embodiments, switches 65A, 65B may be high power relays mounted to a frame or structure of a battery pack.

The configuration of circuit 83 shown in FIG. 8 may be adopted in both an “awake” state of vehicle 10 and an “active” drive state. As described above, in an “awake state”, vehicle 10 is “on” but does not respond to throttle signals from throttle actuator 30. In an “active” state vehicle 10 is also “on” and controller 28 responds to throttle signals from throttle actuator 30 to propel vehicle 10. While in the “awake” state, HV battery 26 may be electrically connected to PEM 64, but the propulsion of vehicle 10 may be prevented by preventing electric power from being delivered to motor 18 via inverter 84. Preventing propulsion of vehicle 10 while switches 65A and 65B are closed may be done by controller 28 not executing (e.g., ignoring) propulsion commands that may be received via throttle actuator 30. Ignoring propulsion commands may include controller 28 keeping the switches of inverter 84 in a configuration where electric power is not supplied to motor 18. In other words, while in the “awake” state, controller 28 may be programmed not to control inverter 84 according to propulsion commands that may be received via throttle actuator 30. When in the reverse requested state and/or the forward requested state, the configuration of circuit 83 may be adopted while controller 28 does not execute (e.g. ignores) commands originating from throttle actuator 30.

FIG. 9 is a flow diagram of a method 1000 of controlling an electric vehicle such as vehicle 10. Method 1000 may include other actions, or may be combined with other methods or actions disclosed. Method 1000 may be carried out using elements of vehicle 10. Functions and other aspects of vehicle 10 may be incorporated into method 1000. Method 100 may be computer-implemented. In various embodiments, method 100 may include: sensing parameter 46 of powertrain 36 of vehicle 10, the powertrain including motor 18 for propelling vehicle 10 and battery 26 for powering motor 18; when parameter 46 is indicative of a non-normal condition of powertrain 36 at decision block 1002 (e.g., using limits data 48). Method 1000 may include: restricting the power that can be generated by powertrain 36 to an available power limit (block 1004), the available power limit being variable as a function of the non-normal condition; and dynamically displaying (e.g., on instrument panel 32) the available power limit to reflect a variation of the non-normal condition (block 1006).

In some embodiments, the available power limit may be selected to mitigate the non-normal condition. For example, the available power limit may be selected to promote mitigation of the non-normal condition when the operation of vehicle 10 is restricted to the available selected power limit.

The dynamic display of the available power limit may display a variation of the power limit to reflect the variation of the non-normal condition substantially in real time. For example, the display of the available power limit may be substantially synchronized with one or more parameters 46 that are indicative of evolving or waning of the non-normal condition.

Returning now to FIG. 5, any available power limit determined using the method 1000 can be applied as presented above.

In accordance with the present invention, while it is desirable to prevent sudden reversals of torque or power output by the electric vehicle, it is also desirable to allow an operator to request transition from the drive state to the reverse state, or vice versa, while the vehicle is in motion. This allows an operator to convey their desire to change vehicle directions at any time during riding, and not just when the vehicle is at rest or stationary. The reverse requested state (or forward requested state) where input commands from the throttle actuator 30 are not executed (e.g. ignored) allows the vehicle to acquire an intermediate state between receiving a reverse request (or forward request) and actually executing a change in direction of the motor 18. Providing an operator-perceptible indication to an operator that the vehicle 10 is in the reverse requested state (or forward requested state) avoids confusion and or frustration at the vehicles' operation during this intermediate state.

As can be understood, the examples described above and illustrated are intended to be exemplary only. The technology presented herein may be used on other types of electric vehicles than snowmobiles in alternate embodiments, such as side-by-sides or other all terrain vehicles for instance. The scope is indicated by the appended claims. 

What is claimed is:
 1. A method of transitioning an electric snowmobile from a drive state to a reverse state, the method comprising: receiving at a controller a reverse request from a user interface of the electric snowmobile; wherein, upon receipt of the reverse request, the controller being operative to: transition the electric snowmobile from a drive state to a reverse state when a speed signal associated with the electric snowmobile is below a predetermined speed threshold, wherein in the reverse state, the controller drives the electric snowmobile in a reverse direction based on a throttle signal; and, transition the electric snowmobile from a drive state to a reverse requested state when a speed signal associated with the electric snowmobile is above a predetermined speed threshold, wherein in the reverse requested state, the controller does not drive operation of the electric snowmobile based on the throttle signal.
 2. The method of claim 1 wherein, when the electric snowmobile is in the reverse requested state, the controller is further operative to: transition the electric snowmobile from the reverse requested state to the reverse state when the speed signal transitions from above the speed threshold to below the speed threshold.
 3. The method of claim 1 wherein, when the electric snowmobile is in the drive state, the controller drives the electric snowmobile in a forward direction based on the throttle signal.
 4. The method of claim 1 wherein the transition from the drive state to the reverse state is contingent upon determining that a throttle signal is below a throttle threshold.
 5. The method of claim 1 wherein the transition from the drive state to the reverse requested state includes changing an indicator configuration in a user interface of the electric snowmobile.
 6. The method of claim 5 wherein said changing the indicator configuration includes at least one of changing a configuration of a visual indicator and changing a configuration of an audible indicator.
 7. The method of claim 1 wherein, when the electric snowmobile is in the reverse requested state, the controller is further operative to: transition the electric snowmobile from the reverse requested state to the reverse state when the speed signal transitions from above the speed threshold to below the speed threshold, and wherein the transition from the reverse requested state to the reverse state includes changing an indicator configuration in the user interface.
 8. The method of claim 1 further comprising generating the reverse request upon operator interaction with a user input on a user interface of the electric snowmobile.
 9. The method of claim 1 further comprising acquiring the speed signal associated with the electric snowmobile, the speed signal comprising at least one of a vehicle speed and a motor speed.
 10. The method of claim 1 wherein driving the electric snowmobile in the reverse direction includes mapping a throttle signal to a corresponding power request based on a power map, and applying the power request to an electric motor of the electric snowmobile.
 11. The method of claim 1, wherein, when the electric snowmobile is in the reverse requested state, the controller is further operative to: transition the electric snowmobile from the reverse requested state to the drive state when a throttle signal above a throttle threshold value is received.
 12. The method of claim 1, wherein in the reverse requested state, the controller drives the electric motor in a regenerative mode to actively decelerate the electric snowmobile.
 13. A snowmobile having a powertrain including an electric motor mechanically engaged with a track, a motoring battery configured for supplying the electric motor with electrical power, a throttle actuator operable to provide a throttle signal changing as a function of a position of the throttle actuator, a speed sensor operable to provide a speed signal associated with the electric snowmobile, a user interface operable to receive a reverse request from a driver of the snowmobile, and a controller having a processor and a non-transitory memory, the non-transitory memory having instructions stored thereon, the instructions being executable by the processor for enabling the controller to: when the controller is in a drive state, operate an electric motor of the electric snowmobile in a forward angular direction based on the throttle signal, and, when the reverse request has been received, transition from the drive state to a reverse requested state; when the controller is in the reverse requested state, negate control of the electric motor on a basis of the throttle signal, and, transition to a reverse state when the speed signal transitions from above a speed threshold to below the speed threshold; and when the controller is in the reverse state, operate the electric motor in the reverse angular direction based on the throttle signal.
 14. The snowmobile of claim 13 wherein said transitioning from the drive state to a reverse requested state is contingent upon determining that the throttle signal is below a throttle threshold value.
 15. The snowmobile of claim 13 wherein said transitioning from the drive state to the reverse requested state includes changing an indicator configuration in the user interface of the electric snowmobile.
 16. The snowmobile of claim 15 wherein said transitioning from the reverse requested state to the reverse state includes changing an indicator configuration in the user interface.
 17. An electric vehicle comprising: an electric motor; a battery configured for supplying the electric motor with electrical power; a throttle actuator operable to provide a throttle signal changing as a function of a position of the throttle actuator; a controller having a processor and a non-transitory memory, the non-transitory memory having instructions stored thereon, the instructions being executable by the processor for enabling the controller to: receive a reverse request from a user interface of the electric vehicle; wherein, upon receipt of the reverse request, the controller being operative to: transition the electric vehicle from a drive state to a reverse state when a speed signal associated with the electric vehicle is below a predetermined speed threshold, wherein in the reverse state, the controller drives the electric vehicle in a reverse direction based on the throttle signal; and, transition the electric vehicle from a drive state to a reverse requested state when a speed signal associated with the electric vehicle is above a predetermined speed threshold, wherein in the reverse requested state, the controller does not drive operation of the electric vehicle based on the throttle signal.
 18. The electric vehicle of claim 17, wherein in the reverse requested state, the controller is further operative to: transition the electric vehicle from the reverse requested state to the reverse state when the speed signal transitions from above the speed threshold to below the speed threshold.
 19. A method of transitioning an electric snowmobile from a drive state to a reverse state, the method comprising: receiving at a controller a reverse request from a user interface of the electric snowmobile; wherein, upon receipt of the reverse request, the controller being operative to: transition the electric snowmobile from a drive state to a reverse state when a speed signal associated with the electric snowmobile is below a predetermined speed threshold, wherein in the reverse state, the controller drives an electric motor of the electric snowmobile in a reverse direction based on a throttle signal; and, transition the electric snowmobile from a drive state to a reverse requested state when a speed signal associated with the electric snowmobile is above a predetermined speed threshold, wherein in the reverse requested state, the controller drives the electric motor in a regenerative mode to actively decelerate the electric snowmobile.
 20. The method of claim 19 wherein in the reverse requested state, the controller sustains the regenerative mode until the speed signal reaches the predetermined speed threshold. 